1. Field of the Invention
The present invention relates to a method for analysis of DNA and the like using capillary array electrophoresis and an apparatus for the analysis.
2. Description of the Related Art
Capillary gel electrophoresis is a rapid and highly sensitive analysis method and is noted as a promising method particularly for DNA analysis including DNA base sequence determination (DNA sequencing). In addition, a capillary array apparatus composed of capillary analyzing tubes put side by side has been developed for increasing the analyzing through-put by analyzing a large number of samples in parallel. In such apparatus, samples are held in a titer plate or a sample bottle, electrodes and the ends of capillaries are put into the titer plate or the sample bottle, and the samples are electrically introduced into the capillaries by application of an electric field between the electrodes and the ends of the capillaries.
On the other hand, there is a growing demand for DNA analysis such as DNA sequencing with the progress of Human Genome Project, and the development of an efficient DNA analysis method is desired. A DNA sequencer using a capillary array gel electrophoresis is also a promising apparatus for the DNA analysis. In addition to such an analyzing apparatus, the improvement of the efficiency of sample preparation and injection into the analyzer has become necessary and various pipetting apparatus are on the market. For preparing samples for DNA sequencing or the like, there is usually used a tube having a capacity of 0.5 ml or a 96-well titer plate. Titer plates are suitable for preparing a large number of samples and are widely used. As to the total volume of reagents used in the reactions carried out in the titer plate, the reaction volume is about 10 .mu.l and cannot be reduced because of the reaction efficiency, and titer plates with a capacity of approximately 100-200 .mu.l are widely used. Substantially the whole amount of the reaction products obtained by the use of a titer plate are used for measurement in a DNA sequencer commercialized with a slab gel, but the amount of samples used in a DNA sequencer using capillaries is one hundredth or less as large as the amount of samples used for measurement using the slab gel. This means that there is a great possibility to reduce the amount, therefore the cost, of reagent(s) used in DNA analysis. However, the conventional sequencing reaction procedure is not suitable for this purpose. Thus, a new tool or method is needed wherein a small amount of reagent is consumed and a small amount of products are efficiently introduced into the capillaries.